Tandem axle suspensions

ABSTRACT

Tandem axle suspensions comprising transversely spaced pairs of bellcranks fulcrumed on adjacent transverse axes to a vehicle frame and having platelike substantially horizontal arms extending longitudinally in opposite directions from their fulcrums, and upright arms having means resiliently biasing the upright arms away from each other through axles secured to corresponding outer ends of the horizontal arms, the horizontal arms lying in longitudinal substantially vertical planes and being torsionally sufficiently flexible to permit transverse tipping of the through axles for operation over irregular surfaces. In one embodiment of the invention, the upright arms are rigid members, with longitudinally acting springs compressed between their upper ends, while in another embodiment the upright arms are semielliptic leaf springs rigidly secured at their lower ends to the horizontal arms and connected by a short strut to each other at their upper ends.

United States Patent [72] Inventor Lloyd J. Wolf 2425 Irving Blvd.,Dallas, Tex. 75207 [2]] App]. No. 844,325 [22] Filed July 24, 1969 [45]Patented Oct. 19, 1971 [54] TANDEM AXLE SUSPENSIONS 10 Claims, 6 DrawingFigs.

[52] U.S. Cl 280/1045, 267/19 511 lm. Cl ..B60g 19/02, B60g 19/08 [50]FieldofSearch 280/1045, 104.5 A; 267/19 [56] References Cited UNITEDSTATES PATENTS 2,614,863 10/1952 Schramm 280/1045 2,869,889 l/l959Dickison 280/1045 A Primary ExaminerPhilip Goodman Attorney-Bedell andBurgess ABSTRACT: Tandem axle suspensions comprising transversely spacedpairs of bellcranks fulcrumed on adjacent transverse axes to a vehicleframe and having platelike substantially horizontal arms extendinglongitudinally in opposite directions from their fulcrums, and uprightarms having means resiliently biasing the upright arms away from eachother through axles secured to corresponding outer ends of thehorizontal arms, the horizontal arms lying in longitudinal substantiallyvertical planes and being torsionally sufficiently flexible to permittransverse tipping of the through axles for operation over irregularsurfaces. In one embodiment of the invention, the upright arms are rigidmembers, with longitudinally acting springs compressed between theirupper ends, while in another embodiment the upright arms aresemielliptic leaf springs rigidly secured at their lower ends to thehorizontal arms and connected by a short strut to each other at theirupper ends.

PATENTEDUET 19 I97! SHEET 10F 2 INVENTOR LLOYD J. WOLF W gt W ATTORNEYSTANDEM AXLE SUSPENSIONS BACKGROUND OF THE INVENTION 1. Field of theInvention The invention relates to land vehicles and consistsparticularly in a tandem axle suspension in which the individual axlesare mounted on bellcranks.

2. The Prior Art In previously disclosed bellcrank suspensions fortandem axles, the bell crank axle support arms have been rigid members.If through axles are secured to the rigid bellcrank arms, independentvertical movement of the wheels on each axle necessitated by uneven roadsurfaces will be prevented by the rigidity of the structure. Attemptshave been made to correct this condition by substitution of stub axlesfor through axles, but although the use of stub axles makes possible thenecessary independent wheel movement, the stub axle structure isinherently weaker than a through axle structure.

SUMMARY OF THE INVENTION The invention provides an opposed bellcranktype of tandem axle suspension having through axles with means forachieving independent vertical movement of all wheels. This objective isachieved by providing torsionally flexible, but otherwise rigid,horizontal axle mounting arms on the bellcranks.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of oneembodiment of the invention.

FIG. 2 is a side elevational view of the embodiment illustrated in FIG.1.

FIG. 3 is a fragmentary transverse vertical sectional view along line3-3 of FIGS. 1 aNd 2.

FIG. 4 is a plan view of a second embodiment of the inventron.

FIG. 5 is a side elevational view of the embodiment illustrated in FIG.4.

FIG. 6 is a transverse vertical sectional view along line 6-6 of FIGS. 4and 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The numeral 1 refers to a pairof transversely spaced longitudinally extending inverted channelmounting elements, connected to each other by a pair of longitudinallyspaced transversely extending transom members 3, and arranged to berigidly connected to a supported vehicle underframe structure, notshown.

At each side of the suspension, a pair of tubular trunnions 5 arerigidly secured to, and protrude transversely outwardly from, mountingelements 1, in slightly spaced relation longitudinally of the vehiclewith respect to each other, but at the same level.

Radial arms each consisting of an elongated torsionallyflexible steelplate 7 are circularly apertured at their inner ends at 9 and tubularbearings 1 1 are welded in the apertures, extending transverselyoutwardly from the vertical planes of plates 7. Bearings 11 are ofsufficient diameter to pivotally receive trunnions 5 which mount collars13 adjacent mounting members 1, and radial arms 7, 11 are rotatablymounted on trunnions 5 with plates 7 abutting collars 13 and therebyspaced from mounting members 1. Arms 7, 11 are mounted on trunnions 5 topoint, longitudinally of the vehicle, away from each other.

The outer ends of arm plates 7 are inwardly slotted as at 15 to receivethe inner ends of wheel spindles 17 on the upright ends of through axles19 which are rigidly secured to the outer ends of radial plates 15.

Pneumatic tired wheels 21 of conventional construction are rotatablymounted on wheel spindles 17 in the usual manner.

For holding bearings 11 in assembled relation with trunnions 5, collars23 are mounted on the outer end portions of trunnions 5 with their innerfaces slidably abutting the outer ends of bearings.

In turn, a bolt 25 passes diametrally through the outer end portions ofthe pairs of trunnions 5 at each side of the suspension to stabilize thetrunnions against rotation, which would tend to weaken their connectionsto mounting members 1, but also to lock collars 23 on the trunnions andthereby maintain arm 7, 11 in assembled relation to trunnions 5.

The structure heretofore described is common to both embodiments of theinvention and the same reference characters will be used to indicatecorresponding elements in the embodiment of FIGS. 4-6.

In the embodiment of FIGS. 1-3, a pair of upstanding channel sectionarms are secured to bearings 11 and radial arm plates 7, with the lowerends of their flanges 27 surrounding and secured to bearings 11 and thelower ends of their inner flanges 27 secured to plates 7 to form, withthe latter, bellcranks having substantially horizontal and vertical armsand fulcrumed on trunnions 5.

Upstanding channel arms include transverse webs 29, and longitudinallyacting compression springs, preferably two-convolution flexible wallpneumatic cushions 31 are interposed between the upper end portions ofwebs 29, being secured thereto by bolts 33, so that, when filled withcompressed gas, such as air, cushions 31 will resiliently oppose pivotalmovement of upstanding arms 27, 29 toward each other and consequentlycushion upward movement of the wheels. On uneven surfaces differentialequalizing movement of the wheels at opposite sides, requiring tiltingof the axles transversely of the vehicle, will be permitted bydifierential pivoting of corresponding arms 7, 11 about their respectivetrunnions 5 and by torsional flexing of plates 7 about theirlongitudinal axes.

The second embodiment of the invention, illustrated in FIGS. 3-6,differs from the first in the construction of the upright arms and theirconnection to each other. In the second embodiment, short channelsection mounting blocks having their flanges 33 semicircularly aperturedare rigidly secured outward of plates 7 to tubular bearings 11 withtheir webs 35 substantially vertical and tangent to the surfaces ofbearings 5 remote from each other.

Substantially upright semielliptic leaf springs 37 are secured againstwebs 35 by rectangular clamping plates 39 each of which is held againstthe outer plates of one of the springs 37 by a pair of U-bolts 41 whichpass around tubular bearings 11 at both sides of the spring and passthrough the corners of clamping plates 39, which are secured by nuts.Springs 37 are curved toward each other longitudinally of thesuspension.

At their upper ends, leaf springs 37 are formed with loops 45 and a pairof longitudinally extending tie bars or links 47 are apertured at theiropposite ends to permit bolts 49 to pass through their respective endsand spring loops 45, thus providing means interposed between springs 37which form the upstanding arms of bellcranks, the longitudinal arms ofwhich are plates 7.

With the construction thus described any upward movement of any of thewheels resulting from ground irregularities will be resiliently opposedby the resistance to distortion of leaf springs 37 opposing each otherthrough links 47, but will be accommodated by the yielding of thesprings. Differential vertical movements of the wheels at opposite sideswill be accommodated by the ability of plates 7 to flex torsionally andthereby permit differential tipping of the axles transversely of thesuspension.

Iclaim:

1. A tandem axle suspension for a vehicle comprising a pair oftransverse axis pivot elements fixed to each side of the vehicle inclosely spaced side-by-side relation longitudinally of the vehicle, apair of arms mounted at their inner ends respectively on said pivotelements at each side and extending longitudinally therefrom in oppositedirections, a pair of wheelmounting transverse through axles rigidlysecured to corresponding outer ends of said longitudinally extendingarms at opposite ends of the vehicle, upstanding elements rigidlysecured respectively to the adjacent inner ends of each arm, meansinterposed between the upper portions of said upstanding elements tooppose their pivotal movements toward each other, said longitudinallyextending arms being vertically rigid but torsionally flexible plateswhereby to freely accommodate transverse tipping of said axles.

2. A tandem axle suspension according to claim 1 whereinsaidlongitudinally extending arm plates are of vertically elongatedcross section.

3. A tandem axle suspension according to claim 1 wherein said upstandingelements are rigid arms, said interposed means comprising a compressionspring device.

4. A tandem axle suspension according to claim 3 wherein said springdevice comprises a flexible wall pneumatic cushion.

5. A tandem axle suspension according to claim I wherein said upstandingelements at each side are leaf springs with their lower ends locatedoutwardly radially of said arms from said pivot elements and with theirupper ends biased toward each other.

6. A tandem axle suspension according to claim 5 wherein said interposedelements at each side are longitudinally extending links pivotallyconnected at their ends to the upper ends of said leaf springs.

7. A tandem axle suspension according to claim 5 wherein said pivotelements are cylinders projecting outwardly from the vehicle sides, saidlongitudinal arms being provided with transversely outwardly projectingtubular elements pivotally surrounding said cylinders.

8. A tandem axle suspension according to claim 7 wherein said leafsprings are secured directly to said tubular elements outwardly of saidlongitudinal arms.

9. A tandem axle suspension according to claim 2 wherein said pivotelements are cylindrical members projecting transversely outwardly fromthe vehicle sides and said longitudinal arms are formed withtransversely outwardly extending tubes pivotally surrounding saidcylindrical elements.

10. A tandem axle suspension according to claim 9 wherein a shoulder isprovided on each said cylindrical element inwardly of said arms toposition said tubes axially of said cylindrical elements, and a collaris mounted on each of said cylindrical elements outwardly of both saidtubes, there being a common bolt extending diametrally of both saidcylindrical elements and said collars to lock the same on saidcylindrical elements and to tie the outer ends of said cylindricalelements to each other against torsional forces applied to them by saidtubes.

1. A tandem axle suspension for a vehicle comprising a pair oftransverse axis pivot elements fixed to each side of the vehicle inclosely spaced side-by-side relation longitudinally of the vehicle, apair of arms mounted at their inner ends respectively on said pivotelements at each side and extending longitudinally therefrom in oppositedirections, a pair of wheel-mounting transverse through axles rigidlysecured to corresponding outer ends of said longitudinally extendingarms at opposite ends of the vehicle, upstanding elements rigidlysecured respectively to the adjacent inner ends of each arm, meansinterposed between the upper portions of said upstanding elements tooppose their pivotal movements toward each other, said longitudinallyextending arms being vertically rigid but torsionally flexible plateswhereby to freely accommodate transverse tipping of said axles.
 2. Atandem axle suspension according to claim 1 wherein said longitudinallyextending arm plates are of vertically elongated cross section.
 3. Atandem axle suspension according to claim 1 wherein said upstandingelements are rigid arms, said interposed means comprising a compressionspring device.
 4. A tandem axle suspension according to claim 3 whereinsaid spring device comprises a flexible wall pneumatic cushion.
 5. Atandem axle suspension according to claim 1 wherein said upstandingelements at each side are leaf springs with their lower ends locatedoutwardly radially of said arms from said pivot elements and with theirupper ends biased toward each other.
 6. A tandem axle suspensionaccording to claim 5 wherein said interposed elements at each side arelongitudinally extending links pivotally connected at their ends to theupper ends of said leaf springs.
 7. A tandem axle suspension accordingto claim 5 wherein said pivot elements are cylinders projectingoutwardly from the vehicle sides, said longitudinal arms being providedwith transversely outwardly projecting tubular elements pivotallysurrounding said cylinders.
 8. A tandem axle suspension according toclaim 7 wherein said leaf springs are secured directly to said tubularelements outwardly of said longitudinal arms.
 9. A tandem axlesuspension according to claim 2 wherein said pivot elements arecylindrical members projecting transversely outwardly from the vehiclesides and said longitudinal arms are formed with transversely outwardlyextending tubes pivotally surrounding said cylindrical elements.
 10. Atandem axle suspension according to claim 9 wherein a shoulder isprovided on each said cylindrical element inwardly of said arms toposition said tubes axially of said cylindrical elements, and a collaris mounted on each of said cylindrical elements outwardly of both saidtubes, there being a common bolt extending diametrally of both saidcylindrical elements and said collars to lock the same on saidcylindrical elements and to tie the outer ends of said cylindricalelements to each other against torsional forces applied to them by saidtubes.